A typical PGA package includes a silicon chip, a package including conductive and non-conductive components and a plurality of pins in a grid array depending downward from a bottom surface of the package. Conventionally, sockets for PGA packages include a plate-like base housing having a plurality of terminals arranged in the same grid pattern as the lead pins of the PGA package and a plate-like cover member having a plurality of through holes in the same grid pattern as the lead pins of the pin grid-array package, thus permitting the lead pins to be inserted in the through holes. The plate-like cover member is slidably positioned on the upper surface of the base housing. Some examples of such sockets are shown in Japanese Patent Application Laid-Open No. 7-142134 and Japanese Registered Utility Model No. 2-536440.
The base housing and cover are slidably interconnected so that the cover is driven in a plane parallel to the underlying base housing between a first position in which the lead pins of the PGA package can pass through the through holes of the cover to reach the terminals mounted in the underlying base housing without requiring any insertion force to be applied to the lead pins and a second position in which the lead pins of the PGA package contact the terminals.
A variety of terminal structures have been proposed as appropriate for use in such sockets. Some such terminals are configured such that their contact portions engage the lead pins of a PGA package upon movement of the cover of the socket, as shown in Japanese Patent Application Laid-Open No. 7-142134 and Japanese Registered Utility Model No. 2-536440 referred to above. Conversely, some terminals are configured such that the lead pins of a PGA package are brought to the contact portions of terminals in the base housing as shown in Japanese Patent Application Laid-Open No. 9-185981.
Essentially all of the terminals have contact portions located in the terminal-receiving cavities of the base housing of the socket, and most have straight pin-like solder tails extending from the bottom of the base housing of the socket. These pin-like solder tails are inserted into through holes of a printed circuit board on which the socket is mounted, and are soldered to the printed circuit board.
The base housing typically has some type of drive mechanism formed thereon for slidably moving the cover over the underlying base housing. In some sockets, a cam is rotatably attached to one lateral side or end of the base housing, and the cam is adapted to be rotated with an associated handle, thereby permitting the cam axle to push or pull the cover over the underlying base housing. The handle may be rotated from a horizontal position in which it is parallel to the base housing to a vertical position in which it is perpendicular to the base housing.
The demand for ever smaller electronic devices has driven the demand for smaller components that make up the electronic devices. However, customers also desire increasing performance from these smaller devices. Thus, component designers must continue to shrink their designs while still improving their performance and ease of use.